Characterization of a New Open Jet Wind Tunnel to Optimize ......Characterization of a New Open Jet Wind Tunnel to Optimize and Test Vertical Axis Wind Turbines Using Flow Visualization

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Characterization of a New Open Jet Wind Tunnel to Optimize and Test Vertical AxisWind Turbines Using Flow Visualization and Measurement

Tourn, S. ; Gilabert, R. ; Sánchez, V. ; Pallares, J. ; Vernet, A. ; Cuesta, I. ; Schmidt Paulsen, Uwe

Publication date:2014

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Citation (APA):Tourn, S., Gilabert, R., Sánchez, V., Pallares, J., Vernet, A., Cuesta, I., & Schmidt Paulsen, U. (2014).Characterization of a New Open Jet Wind Tunnel to Optimize and Test Vertical Axis Wind Turbines Using FlowVisualization and Measurement. Poster session presented at European Wind Energy Conference & Exhibition2014, Barcelona, Spain.

Characterization of a New Open Jet Wind Tunnel to Optimize and Test

Vertical Axis Wind Turbines Using Flow Visualization and Measurement

S. Tourn, R. Gilabert, V. Sánchez, J. Pallares, A. Vernet, I. Cuesta* and U.S. Paulsen**

* Department of Mechanical Engineering. Universitat Rovira i Virgili

**Department of Wind Energy. Technical University of Denmark

PO. ID

233

EWEA 2014, Barcelona, Spain: Europe’s Premier Wind Energy Event

Characterize a new open jet wind tunnel and define the uniform test

section where performance studies of small VAWTs will be carried out.

Objectives Results

Conclusions

Methods

The flow characteristics were analysed by measurements with:

0.1

0.1

0.05

Working grid of

the test section.

A) Single hotwire probe

The measurements were taken in several planes

parallel to the nozzle exit and along the jet axis.

The mean velocity as well as the turbulence

intensity was estimated at every position of the

defined working grid (red points).

BACK VIEW SIDE VIEW FRONT VIEW

B) Cup anemometer

Exit Flow Uniformity and Turbulence Characteristics

x1= 1 m

x2= 2 m

y = 0

x= 1 m

y = 0

-0,8

-0,6

-0,4

-0,2

0,0

0,2

0,4

0,6

0,8

0,00 5,00 10,00 15,00z (

m)

mean speed (m/s)

5,50 m/s at x=1 m 11,20 m/s at x=1 m 15,10 m/s at x= 1 m

5,60 m/s at x= 2 m 11,40 m/s at x=2 m 15,40 m/s at x=2 m

z

-0,8

-0,6

-0,4

-0,2

0,0

0,2

0,4

0,6

0,8

-0,8

-0,6

-0,4

-0,2

0,0

0,2

0,4

0,6

0,8

0,00 5,00 10,00 15,00

z (m

) y (

m)

mean speed (m/s)

5,50 m/s along y 11,20 m/s along y 15,10 m/s along y

5,50 m/s along z 11,20 m/s along z 15,10 m/s along z

z y

-0,8

-0,6

-0,4

-0,2

0,0

0,2

0,4

0,6

0,8

-0,8

-0,6

-0,4

-0,2

0,0

0,2

0,4

0,6

0,8

0 4 8 12 16 20 24 28 32 36 40

z (m

) y (

m)

turbulence intensity (%)

5,50 m/s along y 11,20m/s along y 15,10 m/s along y

5,50 m/s along z 11,20 m/s along z 15,10 m/s along z

z y

-0,8

-0,6

-0,4

-0,2

0

0,2

0,4

0,6

0,8

-0,8

-0,6

-0,4

-0,2

0

0,2

0,4

0,6

0,8

0 4 8 12 16 20 24 28

z (m

) y (

m)

turbulence intensity (%)

5,60 m/s along y 11,40 m/s along y 15,40 m/s along y

5,60 m/s along z 11,40 m/s along z 15,40 m/s along z

Cup anemometer calibration

y = 0,6242x + 0,2968

4,00

6,00

8,00

10,00

12,00

14,00

16,00

18,00

5,0 10,0 15,0 20,0 25,0 30,0

Me

an

Sp

eed

(m

/s)

Cup Anem Output Signal (m/s)

CA PT Lineal (PT)

The final design of the open jet tunnel is original and allows for fair

performance at comparably low cost.

Present fair characteristics in the central section.

Can be operated at constants mean velocities and relatively low

turbulence intensities.

Results of a cup anemometer calibrated an accredited laboratory show

that the test section and conditions can provide new insight of cup

anemometers.

x1= 1 m

x2= 2 m

y = 0 x1= 1 m

x1= 1 m

x2= 2 m

z

y

z

y

x

Coordinate origin

The origin of the coordinate system is in the centre of the nozzle exit

500 500 500 500 1000

Nozzle

Pitot tube

Pitot tube

Uniform test section (800 x 800 mm2)

Measured positions

Pitot tubes positions

Cup anemometer calibrated

WindSensor

Type P 2546A

Risø DTU

The 3D graph presents mean velocity along positive z and y axis

Test section (1500 x 1500 mm2)

Mean speeds by cup anemometer (CA). Average speeds by pitot tubes (PT).

Linear fit obtained in 4-Winds OJWT y=0.6242*x(m/s)/(1/s)+0.297m/s.